I completely second the view of Ferodo DS2500s - I had them on my S2, they are awesome pads. Do they come in a standard fitment for the stock A4 caliper then?
The Ds2500s seem to have an almost magical combination of properties. They bite well from cold (which is when you use your brakes mostly!), they work up to a much higher temperature than stock pads, they have excellent pedal feel, they provide significantly improved braking ability over stock and don't eat discs like some "fast road" pads do. The only downsides are the enormous quantity of dust they produce, and the price.